From patchwork Wed May 11 12:04:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Baolin Wang X-Patchwork-Id: 12846098 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 55A6BC433FE for ; Wed, 11 May 2022 12:04:49 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DC4EC6B0078; Wed, 11 May 2022 08:04:48 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D74BE6B007B; Wed, 11 May 2022 08:04:48 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C3C7E8D0001; Wed, 11 May 2022 08:04:48 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id B53106B0078 for ; Wed, 11 May 2022 08:04:48 -0400 (EDT) Received: from smtpin08.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 8A9F032AE8 for ; Wed, 11 May 2022 12:04:48 +0000 (UTC) X-FDA: 79453330656.08.265CF9D Received: from out30-56.freemail.mail.aliyun.com (out30-56.freemail.mail.aliyun.com [115.124.30.56]) by imf10.hostedemail.com (Postfix) with ESMTP id 84B73C0091 for ; Wed, 11 May 2022 12:04:24 +0000 (UTC) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R191e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e01424;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=32;SR=0;TI=SMTPD_---0VCw.G9V_1652270670; Received: from localhost(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0VCw.G9V_1652270670) by smtp.aliyun-inc.com(127.0.0.1); Wed, 11 May 2022 20:04:31 +0800 From: Baolin Wang To: akpm@linux-foundation.org, mike.kravetz@oracle.com Cc: catalin.marinas@arm.com, will@kernel.org, songmuchun@bytedance.com, tsbogend@alpha.franken.de, James.Bottomley@HansenPartnership.com, deller@gmx.de, mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, ysato@users.sourceforge.jp, dalias@libc.org, davem@davemloft.net, arnd@arndb.de, baolin.wang@linux.alibaba.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH v4 0/3] Fix CONT-PTE/PMD size hugetlb issue when unmapping or migrating Date: Wed, 11 May 2022 20:04:16 +0800 Message-Id: X-Mailer: git-send-email 1.8.3.1 X-Rspamd-Queue-Id: 84B73C0091 X-Stat-Signature: 3n7gdqu9sqyozqq1ny47x7kmnx7rhuof X-Rspam-User: Authentication-Results: imf10.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=alibaba.com; spf=pass (imf10.hostedemail.com: domain of baolin.wang@linux.alibaba.com designates 115.124.30.56 as permitted sender) smtp.mailfrom=baolin.wang@linux.alibaba.com X-Rspamd-Server: rspam09 X-HE-Tag: 1652270664-577187 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hi, Now migrating a hugetlb page or unmapping a poisoned hugetlb page, we'll use ptep_clear_flush() and set_pte_at() to nuke the page table entry and remap it, and this is incorrect for CONT-PTE or CONT-PMD size hugetlb page, which will cause potential data consistent issue. This patch set will change to use hugetlb related APIs to fix this issue, please find details in each patch. Thanks. Note: Mike pointed out the huge_ptep_get() will only return the one specific value, and it would not take into account the dirty or young bits of CONT-PTE/PMDs like the huge_ptep_get_and_clear() [1]. This inconsistent issue is not introduced by this patch set, and will address this issue in another thread [2]. Meanwhile the uffd for hugetlb case [3] pointed by Gerald also need another patch to address. [1] https://lore.kernel.org/linux-mm/85bd80b4-b4fd-0d3f-a2e5-149559f2f387@oracle.com/ [2] https://lore.kernel.org/all/cover.1651998586.git.baolin.wang@linux.alibaba.com/ [3] https://lore.kernel.org/linux-mm/20220503120343.6264e126@thinkpad/ Changes from v3: - Fix building errors for !CONFIG_MMU. Changes from v2: - Collect reviewed tags from Muchun and Mike. - Drop the unnecessary casting in hugetlb.c. - Fix building errors with adding dummy functions for !CONFIG_HUGETLB_PAGE. Changes from v1: - Add acked tag from Mike. - Update some commit message. - Add VM_BUG_ON in try_to_unmap() for hugetlb case. - Add an explict void casting for huge_ptep_clear_flush() in hugetlb.c. Baolin Wang (3): mm: change huge_ptep_clear_flush() to return the original pte mm: rmap: Fix CONT-PTE/PMD size hugetlb issue when migration mm: rmap: Fix CONT-PTE/PMD size hugetlb issue when unmapping arch/arm64/include/asm/hugetlb.h | 4 +-- arch/arm64/mm/hugetlbpage.c | 12 +++----- arch/ia64/include/asm/hugetlb.h | 5 +-- arch/mips/include/asm/hugetlb.h | 9 ++++-- arch/parisc/include/asm/hugetlb.h | 5 +-- arch/powerpc/include/asm/hugetlb.h | 9 ++++-- arch/s390/include/asm/hugetlb.h | 6 ++-- arch/sh/include/asm/hugetlb.h | 5 +-- arch/sparc/include/asm/hugetlb.h | 5 +-- include/asm-generic/hugetlb.h | 4 +-- include/linux/hugetlb.h | 11 +++++++ mm/rmap.c | 63 ++++++++++++++++++++++++-------------- 12 files changed, 87 insertions(+), 51 deletions(-)